title: Antitumor activity of beta-carotene, canthaxanthin  and phytoene.
abstract: Mice were given either beta-carotene or either of two carotenoids with no vitamin A activity--canthaxanthin or phytoene--or placebo. Skin tumors were induced in each group by each of three methods: (1) UV-B (290--320 nm); (2) dimethylbenz(a)anthracene (DMBA)/croton oil applications; (3) DMBA followed by low-dose UV-B. For tumors induced by UV-B alone, beta-carotene-phytoene- and canthaxanthin-treated mice developed fewer tumors per mouse, with a delay in tumor appearance, than did control mice. For tumors induced by DMBA/croton oil or DMBA/UV-B, mice receiving beta-carotene showed a significant difference in tumor numbers and appearance time from placebo mice; phytoene and canthaxanthin treatment had no effect.
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D016644:Canthaxanthin; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced; D002338:Carotenoids / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D003436:Croton Oil; D005260:Female; D051379:Mice; D008815:Mice, Inbred Strains; D009374:Neoplasms, Experimental / Q000139:chemically induced; D009381:Neoplasms, Radiation-Induced / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D010212:Papilloma / Q000139:chemically induced; D012878:Skin Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D014466:Ultraviolet Rays; D019207:beta Carotene
chemical_list: D019207:beta Carotene; D002338:Carotenoids; D016644:Canthaxanthin; D015127:9,10-Dimethyl-1,2-benzanthracene; D003436:Croton Oil; C100185:(all-E) phytoene